It’s easy to compare the current and growing rivalry between Twitter and Plurk to the rivalry experienced by Myspace and Facebook. And with Facebook recently becoming the biggest social network in the world, could Plurk pull the same trick with microblogging?

Well, for starters there are some slight differences in the two rivalries. Although Myspace became the biggest player in social networking, it didn’t have the first player status Twitter has – that honour belonged to the infamous and yet still running Friendster.

Twitter and Myspace do both fall foul of the fact that user customisation sometimes leads to profiles looking like a car crash, but as Twitter tweaking is more limited, it’s escaped the worst excesses. And while Plurk takes a more stylish route, perhaps in the spirit of Facebook, it’s far more overwhelming, with the horizontal timeline, Karma and cartoon icons.

But the biggest difference between Facebook, Myspace , and even Plurk at this stage from Twitter, is that Twitter is powered by mainly third party applications and integrations. It may be the reason the database is unreliable at the moment, but around 90% of queries come from external applications – not direct via the website. There’s just some of the many, many Twitter tools listed here. It isn’t like Facebook or Myspace, which uses applications as a way to add interaction and entertainment to the network. In this case, the applications can be the only entry to the network for many people.

And yet it’s this that makes me think Twitter will remain the leader in microblogging for a while yet, and is a way from peaking. There’s a limit to how many networks people will join, but Twitter apps can increasingly use the technology for their own devices, and can start to utilise Twitter within other websites. For instance, Chirrup uses Twitter to power blog and website comments.

Imagine more companies using Twitter to converse internally, now that more and more people have grown used to Instant Messaging and Facebook. And more public users of Twitter applications, and aggregators like FriendFeed.

I don’t want to overhype Twitter, despite my addiction (@badgergravling). There’s still a need for social networks, forums, Instant Messaging, email, telephones and even snail mail for different functions. I wouldn’t have started a blog about microblogging otherwise! But just as it’s now a rare event for me to use the postal service, and my email influx has waned, microblogging means IM and social networks are replaced by semi-instantaneous Twittering…